The compound, called 4-methylimidazole or 4-MEI, is added to soft drinks and other foods to turn them brown, according to Consumer Reports.

Under California's Proposition 65 law, any food or beverage sold in the state that exposes consumers to more than 29 micrograms of 4-MeI per day is supposed to carry a health-warning label. The testing by Consumer Reports found 12-ounce samples of Pepsi One and Malta Goya had more than 29 micrograms per can or bottle.

Earlier testing by Consumer Reports found more than 29 micrograms in Pepsi, Diet Pepsi and Dr. Snap. Consumer Reports noted it's possible to ingest more than that if someone drinks more than one can of soda a day.

The Consumers Reports testing has prompted the Food and Drug Administration to take another look at the brown food coloring in sodas and other foods, although the agency has said there is no evidence it is unsafe as used.

In 2007, a federal government study concluded that 4-MeI caused cancer in mice and the International Agency for Research on Cancer determined the chemical to be "possibly carcinogenic to humans" in 2011.